Nguyen Van Huong, head of the climate forecast department at the National Center for Hydro-Meteorological Forecasting, said temperatures in the north in summer typically range between 25 and 31 degrees Celsius.

An incoming mass of cold air would not only pull temperatures down by 5-10 degrees, but also cause strong winds in the Gulf of Tonkin and the central coast along with rains in both northern and central regions on Sunday and Monday, he said.

Cold air often flows down into northern Vietnam every May, but not with such intensity, he said.

The wind strength and weather pattern would make the cold wave similar to one seen over a decade ago in May 2011, he added.

Temperatures in Hanoi will be around 21-26 degrees on Saturday before dropping to 20-23 degrees on Monday, according to U.S. weather forecast service AccuWeather.

Mountainous areas like Lao Cai Province's Sa Pa will have temperatures of 13-18 degrees on Saturday.

Northern Vietnam will gradually become warmer after the cold wave, with temperatures reaching 26-30 degrees in Hanoi by Saturday next week.

There will be more cold waves in the north in the latter half of May that will bring rains.

The average temperatures at the end of May and start of June are expected to be lower than in previous years due to effects of La Nina, meteorologists said.

The hottest period in the northern and central regions will be from the end of June to early August, with temperatures potentially crossing 35 degrees Celsius during the day.

Source: VNE